<template>
  <a-cascader
    v-model="state"
    :options="options"
    :load-data="loadData"
    change-on-select
    @change="handleChange"
    :displayRender="handleRenderDisplay"
  >
    <template #suffixIcon v-if="loading">
      <LoadingOutlined spin />
    </template>
    <template #notFoundContent v-if="loading">
      <span>
        <LoadingOutlined spin class="mr-1" />
        {{ t('component.form.apiSelectNotFound') }}
      </span>
    </template>
  </a-cascader>
</template>
<script>
  import { defineComponent, ref, unref, watch, watchEffect } from 'vue';
  import { Cascader } from 'ant-design-vue';
  import { propTypes } from '@/utils/propTypes';
  import { isFunction } from '@/utils/is';
  import { get, omit } from 'lodash-es';
  import { useRuleFormItem } from '@/hooks/component/useFormItem';
  import { LoadingOutlined } from '@ant-design/icons-vue';
  import { useI18n } from '@/hooks/web/useI18n';
  export default defineComponent({
    name: 'ApiCascader',
    components: {
      LoadingOutlined,
      [Cascader.name]: Cascader,
    },
    props: {
      value: {
        type: Array,
      },
      api: {
        type: Function,
        default: null,
      },
      numberToString: propTypes.bool,
      resultField: propTypes.string.def(''),
      labelField: propTypes.string.def('label'),
      valueField: propTypes.string.def('value'),
      childrenField: propTypes.string.def('children'),
      asyncFetchParamKey: propTypes.string.def('parentCode'),
      immediate: propTypes.bool.def(true),
      // init fetch params
      initFetchParams: {
        type: Object,
        default: () => ({}),
      },
      // 是否有下级，默认是
      isLeaf: {
        type: Function,
        default: null,
      },
      displayRenderArray: {
        type: Array,
      },
    },
    emits: ['change', 'defaultChange'],
    setup(props, { emit }) {
      const apiData = ref([]);
      const options = ref([]);
      const loading = ref(false);
      const emitData = ref([]);
      const isFirstLoad = ref(true);
      const { t } = useI18n();
      // Embedded in the form, just use the hook binding to perform form verification
      const [state] = useRuleFormItem(props, 'value', 'change', emitData);
      watch(apiData, (data) => {
        const opts = generatorOptions(data);
        options.value = opts;
      }, { deep: true });
      function generatorOptions(options) {
        const { labelField, valueField, numberToString, childrenField, isLeaf } = props;
        return options.reduce((prev, next) => {
          if (next) {
            const value = next[valueField];
            const item = Object.assign(Object.assign({}, omit(next, [labelField, valueField])), { label: next[labelField], value: numberToString ? `${value}` : value, isLeaf: isLeaf && typeof isLeaf === 'function' ? isLeaf(next) : false });
            const children = Reflect.get(next, childrenField);
            if (children) {
              Reflect.set(item, childrenField, generatorOptions(children));
            }
            prev.push(item);
          }
          return prev;
        }, []);
      }
      async function initialFetch() {
        const api = props.api;
        if (!api || !isFunction(api))
          return;
        apiData.value = [];
        loading.value = true;
        try {
          const res = await api(props.initFetchParams);
          if (Array.isArray(res)) {
            apiData.value = res;
            return;
          }
          if (props.resultField) {
            apiData.value = get(res, props.resultField) || [];
          }
        }
        catch (error) {
          console.warn(error);
        }
        finally {
          loading.value = false;
        }
      }
      async function loadData(selectedOptions) {
        const targetOption = selectedOptions[selectedOptions.length - 1];
        targetOption.loading = true;
        const api = props.api;
        if (!api || !isFunction(api))
          return;
        try {
          const res = await api({
            [props.asyncFetchParamKey]: Reflect.get(targetOption, 'value'),
          });
          if (Array.isArray(res)) {
            const children = generatorOptions(res);
            targetOption.children = children;
            return;
          }
          if (props.resultField) {
            const children = generatorOptions(get(res, props.resultField) || []);
            targetOption.children = children;
          }
        }
        catch (e) {
          console.error(e);
        }
        finally {
          targetOption.loading = false;
        }
      }
      watchEffect(() => {
        props.immediate && initialFetch();
      });
      watch(() => props.initFetchParams, () => {
        !unref(isFirstLoad) && initialFetch();
      }, { deep: true });
      function handleChange(keys, args) {
        emitData.value = keys;
        emit('defaultChange', keys, args);
      }
      function handleRenderDisplay({ labels, selectedOptions }) {
        if (unref(emitData).length === selectedOptions.length) {
          return labels.join(' / ');
        }
        if (props.displayRenderArray) {
          return props.displayRenderArray.join(' / ');
        }
        return '';
      }
      return {
        state,
        options,
        loading,
        t,
        handleChange,
        loadData,
        handleRenderDisplay,
      };
    },
  });
</script>
